Seed metering apparatus seed tube

ABSTRACT

A seed tube for an agricultural implement having a seed metering mechanism for uniformly dispensing seeds. The seed tube defines an enclosed curvilinear seed passageway extending between opposite ends of the tube. To promote control over the seeds gravitationally passing through the tube, the seed passageway has a smooth but decreasing cross-sectional configuration between ingress and egress ends of the passageway. The interior surface of the passageway and preferably the tube itself is formed from a material having a coefficient of surface friction ranging between about 0.02 and about 0.10. The enclosed seed passageway furthermore includes a narrowed front edge extending upwardly from a lower end of, the tube and for a majority of the length of the passageway. The narrowed front edge passes beneath and across, in a fore-and-aft direction, the entire ingress end of the passageway for enhancing control over and such that the individual seeds passing through the passageway have substantially equivalent time therein thus promoting equidistant spacings between seed plantings.

FIELD OF THE INVENTION

The present invention generally relates to agricultural implementshaving mechanisms for metering seed delivery at a controlled rate to theground over which the implement is drawn and, more particularly, to aseed tube for directing seeds from the seed delivery mechanism forgravitational deposit on the ground.

BACKGROUND OF THE INVENTION

Agricultural implements such as planters and grain drills typicallyinclude mechanisms which meter or dispense individual seeds to theground. As the implement is drawn across a field, seeds are preferablydeposited into furrows in the ground. As will be appreciated by thoseskilled in the art, the seeds which are planted vary in size, weight andshape depending upon the particular planting.

Various types of seed metering mechanisms are known in the art. Someseed metering mechanisms are a mechanical type wherein individual seedsare picked from a seed mass and discharged to the ground for depositwithin the furrows by mechanical devices. Other seed metering mechanismsutilize an apertured rotating disk that operates under the influence ofair pressure differentials. Other metering mechanisms rely on a rotatingdrum that picks up seed from a seed mass and delivers the seeds throughelongated air conduits for deposit within the furrows.

Regardless of the type of seed metering mechanism used, it is desirableto deposit a given quantity of seeds within a furrow over apredetennined distance. Also, it is important that the seeds bedelivered to the ground in such a way that adjacent seeds within afurrow are generally equidistantly spaced relative to each other alongthe length of the furrow. To properly deposit the seeds within thefurrow requires not only that the seeds be periodically dispensed fromthe metering apparatus in generally uniform relation relative to eachother, but also that the seeds are directed toward and deposited intothe furrow with minimal disturbance being imparted to the seeds as theypass from the seed metering mechanism to the ground.

In one form, the seed metering mechanism is typically arranged incombination with a seed hopper that is carried by the agriculturalimplement and moves along therewith at some nominal speed. It is knownto mount a series of seed hoppers in side-by-side relation with eachother with each seed hopper having its own seed metering mechanism forcontrolling the discharge of seeds to the ground as the implement ispulled there across.

Proper deposit of the seed into the furrow promotes planting, growing,and subsequent harvesting procedures. If the individual seeds arereleased from a housing of the seed meter for essentially verticalstraight down movement into the furrow below under the effects ofgravity, the ability to positively control the seed deposit is lost.Because the seed meter mechanism is not positioned immediately adjacentto the ground surface, the seeds discharged would normally establish avertical velocity before they strike the ground.

Moreover, and because of the movement of the seed metering mechanismwith the implement, the individual seeds exhausted from the housing ofthe seed metering mechanism likewise have a horizontal component ofmovement. The furrow openings wherein the seeds are to be deposited arecreated in soil and cannot be exact. Thus, the vertical and horizontalvelocity components of the seeds discharged from the seed meteringmechanism frequently cause the seeds to bounce upon engagement with thesoil and away from the intended landing area, resulting in inaccurateand nonuniform distribution of the seeds within the furrow.

To better control the individual seeds as they are discharged from thehousing of the seed metering mechanism, it is known to use a seed tubedepending from a seed discharge area of the seed metering mechanism andextending toward the ground. These known seed tubes have an upperportion with a relatively straight configuration in the seed dischargearea of the seed metering mechanism to provide a relatively smoothreception of the seeds into the tube. Such tubes are also known toinclude a curvature along a lower portion of the tube. The curvedconfiguration at the lower portion of the tube serves a dual purpose.First, the configuration of the tube is curved a sufficient amountrelative to the upper portion of the tube to control the verticalvelocity component of the seed as it gravitationally moves toward adischarge end of the tube. Second, the curved configuration of the lowerportion of the seed tube is such that it minimizes or eliminates thehorizonal velocity component of the seeds as they are discharged to theground. It is known to configure the lower portion of the tube with avertically curved configuration in a direction opposite to the normaldirection of the implement across a field. The seeds are thereby causedto exit from the seed tube with the horizontal velocity component of theseeds being generally equal to and opposite the horizontal velocity ofthe implement over the ground.

While such configured or curved tubes have proven effective incontrolling the vertical velocity component of the seeds as they movethrough the tube while minimizing or eliminating the horizontal velocitycomponent of the seeds moving through the tubes, such seed tubes havebeen known to introduce problems of their own which detract from theadvantages obtained through their use in combination with seed meteringmechanisms. A significant problem involving such seed tube relates tothe inherent tendency for the seeds to rattle or bounce as they movethrough the tube. The vibrations inherent with the seed tube as it movesacross the field exacerbates the seed deflection and delivery problems.Moreover, and because the seeds exhausted from the housing of the seedmetering mechanism are of different sizes and shapes, each seed willhave a different surface friction contact which tends to slow, delay andalter seed travel as it moves between upper and lower ends of the seedtube. As a result of such bouncing and frictional engagement with thetubes the seeds tend to exit the seed tube at different times and inunpredictable manners As will be appreciated, the inability to maintainsubstantially equidistance spacing between the seeds as they travelthrough the tube while likewise losing the ability to maintainsubstantially constant or uniform discharge of the seeds from the tube,results in nonuniform seed spacings within the furrow.

Thus, there is a need and a desire for a seed tube which is adapted toreceive seeds from a seed metering mechanism and which is capable ofcontrolling gravitational movement of the seeds by minimizing surfacefriction and seed bouncing as the seeds move along a predeterminedpathway thereby enhancing controlled delivery of the seeds to theground.

SUMMARY OF THE INVENTION

In view of the above, and in accordance with the present invention,there is provided a seed tube including a hollow member defining anenclosed and vertically curved seed pathway extending lengthwise betweenupper and lower ends of the hollow member. The pathway is defined by anarrowed front edge extending upwardly from the lower end of the seedtube and along the majority length of the hollow member with surfacesangularly diverging rearwardly in opposite directions from the forwardedge toward a rear surface. The angularly diverging surfaces of the seedtube extend from the front edge in opposite directions and tend topositively direct the seeds moving along the pathway toward the narrowedfront edge and limit the area in which the seeds can bounce therebyfacilitating their equidistance spacing relative to each other andenhancing delivery of the seeds to the ground

The majority of the length of the interior surface defining the seedpathway has a coefficient of surface friction ranging between about 0.02and about 0.10. This low surface friction further serves to eliminateincreases in spacing between the seeds resulting from seed contactregardless of the seed size and shape. In a most preferred form of theinvention, the tube is formed from a molybdenum disulfide filled nylonmaterial or the like material having a coefficient of surface frictionwith the characteristics described above.

Preferably, the enclosed seed pathway defined by said tube has afunnel-like configuration between upper and lower ends thereof. That is,the seed pathway has a larger cross section toward the upper end of themember than toward the lower end so as to promote uninhibited receptionof seeds within the tube.

In a preferred embodiment of the invention, the angularly divergingsurfaces extending rearwardly from the front edge form a "V" shapedconfiguration defining an included angle, ranging between about 60° andabout 135°, between the angularly diverging surfaces. As will beappreciated, any angle suitable to promote positive displacement of theseeds toward the front edge as the seeds gravitationally move along thepathway will suffice. Moreover, the front edge extends along themajority of the internal surface and is configured with a curvaturehaving a radius ranging between about 0.062 inches and about 0.562inches. The curvature of the front edge extends outwardly away from theseed pathway and into planes of the diverging and angularly disposedsurfaces extending rearwardly from the front edge.

In one embodiment of the invention, the seed tube is arranged incombination with a seed metering apparatus comprising a housing mountedto be moved over ground in a predetermined direction and having a hollowinterior configuration defining a hopper area wherein seeds are held Theseed metering apparatus further includes a rotary and apertured diskmounted within the hollow interior of the housing for conveying seeds ofthe housing for conveying seeds from the hopper to a seed discharge areaunder the influence of pressure differentials acting on the disk. Thepressure differentials acting on the disk are blocked in the region ofthe seed discharge area such that seeds are periodically released fromthe disk within the seed discharge area of the housing for deposit tothe ground. The upper end of the seed tube is arranged in seed receivingrelation relative to the seed discharge area of the housing.

As mentioned above, the interior seed pathway defined by the seed tubehas a vertically curved configuration. The configuration of the interiorpassageway is curved in a direction opposite the direction of movementof the seed metering device. The curved configuration of the seedpathway or passageway is such that the vertical and horizontalcomponents of the seeds moving through the passageway are controlledsuch that the seed will eventually simply slide along the narrowedforward or front edge of the tube as it approaches the lower end fromwhence the seeds are discharged. The curvature of the tube, combinedwith the low coefficient of surface friction and the angularly divergingsurfaces extending rearwardly from the front edge of the tube deadensseed bounce and allows the seeds to be discharged into the furrow withsubstantially equidistant spacing between the seeds.

These and other aims, objects and advantages of the present inventionwill be apparent from the following detailed description, appendedclaims, and the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevational view of a planting unit with aseed tube in accordance with the present invention depending from a seedmetering mechanism;

FIG. 2 is an enlarged schematic side elevational view of a portion ofthe seed metering mechanism illustrated in FIG. 1 with parts broken awayto show a rotatable disk of the seed metering mechanism that plucksindividual seeds from a seed mass and then discharges the seeds from theseed metering apparatus into a seed tube of the present invention;

FIG. 3 is an enlarged schematic and side elevational view of the seedtube having a sensor mounted toward the lower end thereof;

FIG. 4 is a side elevational view of one form of a seed tube accordingto the present invention;

FIG. 5 is a front elevational view of the seed tube as schematicallyillustrated in FIG. 4;

FIG. 6 is a plan view of the seed tube schematically illustrated in FIG.4;

FIG. 7 is a sectional view of the seed tube taken along line 7--7 ofFIG. 4;

FIG. 8 is a sectional view taken along line 8--8 of FIG. 4;

FIG. 9 is a sectional view taken along line 9--9 of FIG. 4;

FIG. 10 is a rear view of the discharge area of the seed tube shown inFIG. 4;

FIG. 11 is an enlarged schematic sectional view of a lower area of theseed tube with a sensor arranged in operable association with the seedtube for detecting the passage of seeds through the seed tube;

FIG. 12 is an enlarged sectional view taken along line 12--12 of FIG. 3;

FIG. 13 is a view similar to FIG. 3 showing an alternative seed tubeembodiment according to the present invention particularly suited forsmaller size seeds and having a sensor secured to the lower end thereof;

FIG. 14 is a side elevational view of the seed tube schematicallyillustrated in FIG. 13;

FIG. 15 is a front elevational view of the seed tube schematicallyillustrated in FIG. 14;

FIG. 16 is a sectional view taken along line 16--16 of FIG. 14;

FIG. 17 is a sectional view taken along line 17--17 of FIG. 14;

FIG. 18 is a sectional view taken along line 18--18 of FIG. 14;

FIG. 19 is a rear elevational view of the discharge end of thealternative embodiment of seed tube schematically illustrated in FIG.14; and

FIG. 20 is sectional view of another alternative configuration of a seedtube according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is susceptible of embodiment in variousforms, there is shown in the drawings and will hereinafter be describedpreferred embodiments of the invention with the understanding that thepresent disclosure is to be considered as setting forth exemplificationsof the invention which are not intended to limit the invention to thespecific embodiments illustrated.

Referring now to the drawings, wherein like reference numerals indicatelike parts throughout the several views, an agricultural implement isschematically illustrated in FIG. 1 and is represented in its entiretyby reference numeral 10. Implement 10 includes an elongated tool bar 12which is supported for movement across and over fields by a plurality ofwheels (not shown) and which is adapted to be towed in a given forwarddirection by a power source such as an off-highway tractor or the like.Attached to the tool bar 12 are a plurality of planting units 14; withonly one planting unit being shown and described in detail and fromwhich a complete understanding of the present invention may bedetermined. As is well known in the art, the planting units 14 aremounted in side-by-side relationship relative to each other along thelength of the tool bar 12.

In the illustrated form, each planting unit 14 preferably includes aconventional furrow opening apparatus generally indicated in FIG. 1 byreference numeral 18. As is known in the art, the furrow opening unit 18preferably includes a pair of laterally spaced furrow opener disks 21, afurrow forming point 22, and an opener shoe 24. The planting unit 14further includes a pair of furrow closer disks 26 and a press wheel 28arranged in fore-and-aft relationship relative to each other.

A seed hopper 30 is likewise carried on each planting unit 14. A seedmetering mechanism or apparatus 32 is arranged in seed receivingrelation relative to the hopper 30 and, in the illustrated embodiment,forms part of the planting unit 14. The purpose of the seed meteringapparatus or mechanism 32 is to uniformally release seeds for depositonto the ground.

As the power source or tractor pulls the tool bar 12 over the ground, inthe given forward direction, the furrow opener apparatus 18 operates toopen a furrow in the ground. Seeds from the seed hopper 30 flow into theseed metering mechanism 32 from whence seeds are deposited to the groundat a controlled rate. The furrow closer 26 trails the furrow openingapparatus 18 and, as the implement is drawn across the field, serves toclose the furrow together and over the seeds dispensed by the seedmetering mechanism 32 into the open furrow. The trailing press wheel 28serves to compact the soil closed over the seeds In the illustratedembodiment, a pesticide hopper 34 is mounted toward a rear end of eachplanting unit 14 Hopper 34 preferably contains an insecticide and isprovided with conventional dispensing means for applying controlledamounts of insecticide where desired in connection with the planting ofseeds by each planting unit 14.

The seed metering mechanism or apparatus 32 is mounted to and movablewith the hopper 30 in a conventional manner. Suffice it to say, and asshown in FIG. 2, the seed metering apparatus 32 includes a housing 38mounted to be moved over the ground in a predetermined direction. In theillustrated embodiment, housing 38 includes a half shell 40 with aseparating wall or baffle 42 and a cover 44. Cover 44 is of somewhatsimilar configuration to and is operably coupled in abuttingrelationship with the half shell 40 of housing 38. Housing 38 has ahollow interior that defines a seed reservoir 46 disposed to one side ofseparating wall or baffle 42 and wherein a mass of seeds, received fromthe seed hopper 30 are to be held. A rotary and apertured disk 48 ismounted within the hollow interior defined by the housing 38.

As is known in the art, disk 48 defines a series of seed holes oropenings 50 circumferentially arranged in predetermined relationrelative to each other and proximate to the periphery of the disk 48.Individual seeds from the seed reservoir 46 are drawn to and releasablyheld in each hole or opening 50 in the disk 48 by the effect of airpressure differential acting on the disk 48. More specifically, in theembodiment of seed metering mechanism illustrated, seeds are drawn toand releasably held in the holes or openings 50 defined by the disk 48by the effects of an adjustable pressure from a vacuum source (notshown) coupled to the hollow interior of the housing 38.

The individual seeds are carried with the rotating disk 48 until theyreach a seed discharge area 54 defined by housing 38 on the oppositeside of the separating wall or baffle 42 and which is isolated from thereduced pressure within the interior of housing 38. As the holes oropenings 50 move into the seed discharge area, the pressure differentialacting on the disk 48 is closed off, resulting in equalization of airpressure acting on the disk 48 so that the seeds are no longer retainedin the holes or openings 50 as a result of the pressure differential andgravity acting thereon and the seeds are released for discharge from theseed metering mechanism 32. Because the holes or openings 50 on the seeddisk 48 are equidistantly spaced relative to each other, the seedsreleased from the disk 48 will have substantially equidistant spacingsrelative to each other as they pass or fall from the discharge area 54of housing 38. Individual seeds are typically released from the disk 48when each hole or opening 50 reaches approximately a "3 o'clock"position on the split housing 38.

A "3 o'clock" seed release position is generally preferred in seedmetering mechanisms 32 of the type shown in FIGS. 1 and 2 because itallows the direction of seed to exit from the seed metering mechanism 32to be aligned with the direction of gravitational pull. This providesfor relatively uniform seed delivery within a wide range of possiblerotational speeds of the seed disk 48.

For reasons known to those skilled in the art, and depending upon theparticular manufacturer and other considerations, the seed dischargearea 54 of a conventional seed metering mechanism or apparatus 32 isdisposed above the ground surface a distance ranging between about 12inches to about 24 inches The generally vertical release of individualseeds from the seed metering apparatus 32 would normally cause theindividual seeds to gravitationally fall straight down to the groundbelow with a velocity, as mentioned above, that would cause the seeds tobounce upon ground engagement, resulting in nonuniform seeddistribution. With the implement 10 being towed across the field in agiven direction, a horizontal velocity component would likewise beimparted to the individual seeds discharged from the seed meteringapparatus 32. This horizontal velocity component is likewise undesirablebecause of the nonuniformities in seed distribution that could result.

Consequently, and according to a first embodiment of the presentinvention shown in FIG. 3, a seed tube 56 is disposed between the seeddischarge area 54 of each seed metering mechanism or apparatus 32 andextends closely proximate to the ground surface wherein seeds are to bedeposited. According to this first embodiment of the present invention,and as shown in FIG. 3, the seed tube 56 preferably includes anelongated hollow member 58 defining an enclosed seed pathway 60. Member58 has upper and lower ends 62 and 64, respectively. The upper end 62 oftube 56 defines an ingress area 66 to the passageway 60. As will beappreciated, the ingress area 66 is arranged in seed receiving relationwith the seed metering apparatus 32. The lower end 64 of tube 56 definesan egress area 68 from whence seeds are deposited to the ground.

The enclosed seed pathway 60 and preferably tube member 58 has avertically curved configuration between the upper and lower ends 62 and64, respectively, of member 58 such that the ingress and egress areas 66and 68, respectively, of the pathway 60 are disposed in differentplanes. The curved configuration of the pathway 60 extends rearwardly ina direction opposite the forward given direction of the seed meteringapparatus 32. Preferably, and as shown in FIG. 19 the tube 56 furtherincludes an apertured mounting lug 70 for mounting the tube 58 to theplanting unit 14.

Tube 56 offers several distinct and different features for controllingthe seeds as they move along the pathway 60. First, at least theinterior surface of the enclosed passageway 60 has an extremely lowcoefficient of surface friction in the range of about 0.02 to about0.10. In a most preferred form of the invention, the tube 56 is formedor molded from a molybdenum disulfide nylon filled material or similarmaterial having a coefficient of surface friction in the above range,thus promoting gravitational movement of the seeds as they move alongthe pathway regardless of their size and/or shape. Second, the interiorsurface 62 of member 58 is specifically configured to minimize seedrattle or bounce therein so that control can be maintained over themetering of the seeds as they pass from the seed metering apparatus 32to the ground.

As shown in FIGS. 4 and 5, the ingress opening 66 at the upper end 62 ofmember 58 preferably has a larger cross sectional area than does theegress opening 68 at the lower end 64 of member 58. Between its ends,and as will be appreciated from the schematic illustrations in FIGS. 4through 9, the cross sectional area of the enclosed pathway 60 of thetube 56 smoothly changes as a function of the length of the tube. Assuch, and as the seeds move closer to the discharge opening 68 definedby tubular member 58, there is less area for the seeds to bounce andmove as compared to the upper end of the seed tube 56.

Toward its upper end 62, and as shown in FIGS. 6 and 7, the enclosedpassageway 60 is defined by a rear interior surface or wall 72, a pairof opposed side surfaces or walls 74 and 76 connected to and extendingforwardly from the rear wall 72, and a front interior surface or wall 78joined to each side wall 74 and 76. As will be appreciated from theschematic illustrations in FIGS. 6 and 7, the interior surfaces 72, 74,76 and 78 smoothly converge or taper inwardly toward each other as thetube 56 extends from an upper end thereof whereby reducing the crosssectional area of the enclosed passageway 60 thus limiting the seedbounce and rattle as the seeds gravitationally move between oppositeends 62 and 66 thereof.

As shown in FIGS. 4, 7 and 8, the front wall 78 of the passageway 60smoothly tapers and converges into a leading front or forward edge 80.Notably, the forward edge 80 of the interior passageway 60 is narrowedand generally centralized between the side surfaces 74, 76 of the seedpathway 60. The narrowed forward edge 80 extends upwardly from the lowerend 66 and along the majority of the length of the passageway 60.Moreover, the front or forward edge 80 preferably follows the verticallycurved configuration between the upper and lower ends 62 and 64 ofmember 58.

Turning to FIGS. 8, 9 and 10, along that portion of the pathway 60including front edge 80, the interior of the pathway further includesslanted surfaces 82 and 84. The surfaces 82, 84 angularly divergerearwardly in opposite directions relative to each other from theforward edge 80 and toward the rear wall or surface 72 of the interiorof pathway 60 to form a "V" shaped configuration extending along a majorlengthwise portion of the front edge 80. The surfaces 82 and 84 definean included angle therebetween and. in the illustrated embodiment, areintegrally joined to and formed with the side surfaces 74 and 76. Theincluded angle defined between the interior surfaces 82 and 84 of thepassageway 76 ranges between about 60° and about 100°. In a mostpreferred form of the invention, the included angle defined between thesurfaces 82 and 84 of the interior pathway 76 is about 90°.

The front or forward edge 80 of pathway 60, along with the surfaces 82and 84 diverging rearwardly and angularly from edge 80, generally followand parallel the vertically curved configuration of the tube 56 betweenthe upper and lower ends 62 and 64, respectively. As such, and as shownin FIG. 4, the curved forward edge 80 and the surfaces 82, 84 (FIG. 8)extending rearwardly therefrom, curve in a direction opposite the givenforward direction of the seed metering apparatus 32 and extend beneathand across, in a fore-and-aft direction, the width of the upper end 66of passageway 60. Accordingly, as the individual seeds are released fromthe metering apparatus and gravitationally move through the passageway60, they inescapingly engage and are controlled by the edge 80 andsurfaces 82, 84 of the interior passageway 60. As will be appreciated,as the seeds gravitationally fall and engage surface 82 they will bepositively directed by the slanted configuration thereof toward thenarrowed and centered forward edge 80 of the pathway 60. Alternatively,as the individual seeds fall and engage surface 84 they likewise will bepositively directed by the slanted configuration of surface 84 towardthe narrowed and centered forward edge of the pathway 60.

Individual seed size varies depending upon the particular crop beingplanted. As shown in FIGS. 8 though 10, the front interior edge 80 ofthe pathway 60 has a curved configuration extending preferably along theentirety but at least along the majority of the length of the forwardedge 80. The curved configuration extending along the forward interioredge 80 has a radius ranging between about 0.062 inches and about 0.562inches. Moreover, the curved configuration of the interior edge 80extends outwardly away from the pathway 60 and into planes of thediverging and angularly disposed surfaces 82 and 84 extending rearwardlyfrom the front edge 80. The radial configuration of the forward edge 80inhibits smaller seeds from becoming entrapped between the oppositelyslanted surfaces 82 and 84.

Returning to FIG. 3, in a preferred form of the invention, the seed tube56 has a conventional sensor or monitoring apparatus 86 arranged inoperable combination therewith. As shown, the monitoring apparatus 86 isoperably arranged in any suitable manner toward the lower end 66 of thetube 56 to provide a more accurate monitoring of the individual seedspassing through the passageway 60. In the illustrated embodiment, thesensor 86 is mounted on the front and rear sides of seed tube 56. In amost preferred from of the invention, the monitoring apparatus 86 isoperably arranged relative to the tube 56 such that it is approximately6 inches or less from the ground.

As shown in FIG. 11, the monitoring apparatus 86 is preferably comprisedof a conventional photodetector including an electric light source 88and an electric sensor or eye 90. As well known in the art, thephotodetector is capable of producing output signals indicative ofindividual seeds passing between the light source 88 and the sensor oreye 90. The output signals are converted to a readout that is preferablyprovided to the operator in a cab region of the tractor (not shown) usedto tow the implement 10 (FIG. 1) across the field.

As will be discussed in further detail below, the configuration of theinterior surfaces defining the enclosed passage 60 of tube 56 are suchthat individual seeds have a tendency and likelihood to slide along thenarrowed front edge 80 between the slanted oppositely directed surfaces82, 84 extending rearwardly from the front edge 80. Accordingly, it ismost beneficial to position the monitoring apparatus where it has thegreatest likelihood of detecting individual seed passing along thepassage 60. In this regard, and turning now to FIG. 12, in a mostpreferred form, the sensor or eye 90 is arranged in operable combinationwith the front edge 80 and the interior surfaces 82, 84 of the pathway60. So as to not interfere with and, thus, reduce the likelihood ofimparting seed rattle or bounce to the seeds passing along the interiorsurfaces of passage 60, at least that end portion of the photodetectorcomponent arranged in operable combination with the front edge 80 of theenclosed passage 60 has a surface configuration that corresponds to issubstantially similar to the configuration of the front or forward edge80 defining a portion of the pathway 60.

Another embodiment of the seed tube is schematically illustrated inFIGS. 13 through 19 and is generally designated therein by referencenumeral 156. The seed tube 156 is similar, and functions in a similarmanner, to the first embodiment of the seed tube 56 described above withreference to FIGS. 3 through 12. This particular embodiment of the seedtube is designed for handling smaller size seeds. The elements of thisalternative embodiment of seed tube 156 that are identical orfunctionally analogous to those of the first embodiment 56 aredesignated with reference numerals identical to those used for the firstembodiment with the exception that this alternative embodiment referencenumerals are in the one-hundred series.

As shown in FIGS. 13 and 14, the seed tube 156 includes a hollow member158 having an elongated configuration. Member 158 defines an enclosedseed passageway 160 that is vertically curved between opposite ends 162and 164 of member 158. Notably, and as with passageway 60 of member 58,the cross-sectional area of the passageway 160 defined by member 158decreases between ingress and egress ends 166 and 168, respectively, ofpassageway 160. Moreover, the curved configuration of the pathway 160extends rearwardly in a direction opposite to the given forwarddirection of the seed metering apparatus 32 (FIG. 1). Intermediate theends thereof, member 158 includes a mounting lug 170 for facilitatingreleasable attachment of tube 156 to the planting unit 14 (FIG. 1).

To facilitate gravitational movement of the individual seeds from theseed metering mechanism 32 toward the outlet end 164 of tube 156, atleast the interior surface of the enclosed passageway 160 has anextremely low coefficient of surface friction in the range of about 0.02to about 0.10. As with tube 56, tube 156 is preferably molded or formedfrom a molybdenum disulfide nylon filled material or similar materialhaving a coefficient of surface friction in the above range.

As shown in FIGS. 14 through 16, toward its upper end the enclosedpassageway 160 is defined by a rear interior surface or wall 172, a pairof opposed side surfaces or walls 174 and 176 connected to and extendingforwardly from the rear wall 172, and a front wall 178 joined to eachside wall 174 and 176. The interior surfaces 172, 174, 176 and 178smoothly converge or taper inwardly toward each other to decrease thecross-sectional configuration of the pathway 160 between upper and lowerends 162 and 164 of tube 156.

As shown in FIG. 15, and as will be appreciated from a comparison ofFIGS. 16 and 17, the front wall or interior surface 178 of the enclosedpassageway 160 smoothly tapers and converges into a narrowed leading orforward edge 180. Notably, the forward edge 180 extends along themajority length of the passageway 160 and is generally centralizedbetween the interior surfaces 174 and 176 of the seed passageway 160.

As shown in FIGS. 17 and 18, along that portion of the enclosedpassageway 160 including the front edge 180, the interior of the pathwayfurther defines interior surfaces 182 and 184. As shown, surfaces 182and 184 angularly diverge rearwardly in opposite directions relative toeach other from the narrowed forward edge 180 and toward the rearsurface or wall 172 of the interior of the passageway 160 to provide amajor lengthwise portion of the front edge 180 with a generally "V"shaped configuration. Notably, the angularly diverging rear surfaces 182and 184, toward their rear ends are, preferably, joined to the sidesurfaces 174 and 176 of the interior surface of the passageway 160. Theangularly diverging interior surfaces 182 and 184 define an includedangle ranging between about 60° and about 135° therebetween.

As shown in FIGS. 13 and 15, the curved forward edge 180 and thesurfaces 182 and 184 extending rearwardly therefrom, curve in adirection opposite from the given forward direction of the seed meteringapparatus 32 (FIG. 1). Moreover, between the vertically spaced ends ofmember 158, the forward edge 180 and surfaces 182 and 184 extend beneathand across, in a fore-and-aft direction, the width of the upper end ofthe member 158. Accordingly, as the individual seeds are released fromthe seed metering apparatus 32 and gravitationally move through thepassageway 160, the seeds inescapingly engage and are controlled by theedge 180 and the surfaces 182, 184 of the interior passageway 160.

As shown in FIGS. 17 and 19, the discharge end 164 of tube member 158has a relative short length. That portion of tube member 158 extendingupwardly from the discharge end 164 has a generally circular outersurface configuration. The interior surface of tube member 158 definedby side surfaces 174, 176, and the front edge 180 with the angularlydiverging surfaces 182 and 184 extending therefrom, all smoothlyconverge into the crosssectional shape illustrated in FIG. 19. Notably,the interior of surfaces 182, 184 combine to define a "V" shapedconfiguration extending along the front edge 180 preferably to thedischarge end 164 of tube member 158. As such, there are no surfaces oredges spaced along the length of the interior surface of the seedpathway 160 that would tend to impart bounce or rattle to the individualseeds moving between opposite ends of the tube 156.

The outer surface configuration at the discharge end 164 of tube 156furthermore promotes the releasable attachment of a conventional outputsignal producing monitoring apparatus or sensor 186 in operableassociation with the discharge end of tube 156. As mentioned above,arranging the monitoring apparatus 186 closer to the ground is bettersuited to monitor the passage of seeds through the tube 156.

Still another embodiment of the seed tube is schematically illustratedin FIG. 20 and is generally designated therein by reference numeral 256.The seed tube 256 preferably has an hollow elongated configurationsubstantially similar to that schematically illustrated in FIGS. 4 or14. The seed tube 156 is intended to function in a manner similar toeither of the two embodiments discussed above. Suffice it to say, theseed tube 256 has a vertically curved configuration between oppositeends thereof. The curved configuration of tube 256 is in a directionopposite to the given forward direction of the seed metering apparatus32 (FIG. 1).

Seed tube 256 further defines an enclosed passageway 260 for guiding andcontrolling individual seeds as they gravitationally move betweenopposite ends of the tube 256. Similar to the above-describedembodiments of the invention, and to facilitate gravitational movementof the individual seeds, the interior surface of the enclosed passageway260 has an extremely low coefficient of surface friction in the range ofabout 0.02 to about 0.06. As with the other embodiments of the presentinvention, tube 256 is preferably formed from a molybdenum disulfidenylon filled material with a PTFE friction modifier added thereto soldunder the tradename "Nylatron GS" or similar material as long as thechosen material has a coefficient of surface friction in the preferredrange mentioned above and has an anti-bounce or "deadening"characteristic thereto.

The tube 256 is characterized by the enclosed passageway 260 having aconfiguration that promotes controlled delivery of individual seeds withminimum bounce and rattle as they move between opposite end of the tube256. In the illustrated embodiment of the invention, and toward theupper end, the enclosed seed pathway 260 defined by tube 256 has agenerally rectangular cross-sectional configuration similar to thatschematically illustrated in FIGS. 6 and 7. To enhance control over theindividual seeds as they pass between opposite ends of the tube 256, therectangular cross-section of the seed pathway 260 smoothly and gentlytransforms to an elliptical cross-sectional configuration as shown inFIG. 20.

As will be appreciated, from the upper location where the rectangularcross-section of the seed pathway transforms to an ellipticalcross-sectional configuration and the discharge end of the tube 256, theelliptical cross-section of the seed pathway continues to decreasethereby providing less and less space for the seeds to bounce and moveor rattle as they move along the pathway 260. As shown in FIG. 20, theelliptically shaped pathway 260 has interior surfaces 274 and 276extending in opposite angular directions away from a narrowed forward orleading edge 280. As in the other embodiments of the invention discussedabove, the front edge 280 of the seed pathway curves upwardly frombeneath and, in a fore and aft direction, crosses the open inlet oregress end to the pathway 260. As the seeds progress downwardly throughthe pathway, if they do not slide along the front edge 280, the sideinterior surfaces 274 and 276 tend to positively impart at least acomponent of movement tending to cause the seeds to move toward thefront edge 280 and thereby reduce the rattle and bounce of the seeds.

Since the various embodiments of the present invention operate in asubstantially similar manner relative to each other, only a summary ofthe unique characteristics of seed tube 56 will be discussed in detailwith the understanding that the other seed tubes and their ownindividual unique characteristics are intended to be encompassed withinthe spirit and scope of the present invention. It was previously notedthat the seeds are released with substantially equal spacingtherebetween from the disk 48 of the seed metering apparatus 32 atessentially the "3 o'clock" position considering the rotary path of thedisk 48. As such, the mean direction of the seeds released from the seedmetering mechanism is essentially vertically downward.

Forming the seed tube of the present invention from any of a class ofmaterials including a nylon 6/6 with a PTFE friction modifier addedthereto and sold under the tradename "Nylatron GS" or a bay resin with aPA111 additive added thereto or other suitable material advantageouslyprovides the interior surface of the enclosed seed passageway 60 with acoefficient of surface friction ranging between about 0.02 and about0.10. Accordingly, and regardless of the shape or size of the individualseeds moving along the pathway 60, the result is that the initialcontact of the individual seeds released and falling from the seedmetering apparatus 32 with the interior surface of the seed pathway willhave less bounce or rattle than heretofore known Testing using highspeed photography, conventional monitoring systems and seed spaceanalyzers has revealed that the extremely low coefficient of surfacefriction provided along the interior seed contacting surfaces of theseed pathway causes the individual seeds to slide relative to thecontacting surface of the pathway rather than bounce or rattle uponcontact and produces what may be best described as a "deadening" oranti-bounce characteristic. Additionally, the extremely low coefficientof surface friction allows the seeds to slide along the interior surfaceof the tube without effecting the speed with which the seeds move asthey pass between opposite ends of the tube. As will be appreciated bythose skilled in the art, deadening the seed by substantiallyeliminating seed rattle and bounce within the tube results in agenerally uniform time it takes for each individual seed to progressbetween the ingress and egress ends of the pathway thereby enhancingequidistant spacing between adjacent seeds during the plantingoperation.

The downwardly curved configuration of the interior surface of the seedpassageway 60 furthermore serves to reduce seed rattle and bounce as theindividual seeds gravitationally move between opposite ends and throughthe tube 56. The rearwardly curved configuration of the interior surfaceof the seed pathway tends to nullify the component of horizontalmovement imparted to the seeds as a result of the forward movement ofthe implement in a given forward direction Moreover, the rearwardly anddownwardly curved configuration of the interior surface of tube 56 tendsto minimize the angle of incidence of seed contact with the interiorsurface of the seed pathway 60.

As schematically illustrated in FIG. 3, a dash line 57 represents themean path of seeds released from the seed metering mechanism 32. Uponrelease from the seed metering mechanism 32, seeds tend to fallessentially vertically downward through the ingress end 66 of the tube56 and into initial contact with the interior surface of the seedpathway 60. Because of the curvature of the interior surface of thepathway 60 (and partially because of the significantly loweredcoefficient of surface friction), the angle of incidence establishedbetween the path of the falling seed and the vertical slant of theinterior surface is relatively small. As will be appreciated by thoseskilled in the art, the continuous rearward and vertically slantedcurvature of the interior surface of the pathway 60 tends to furtherreduce the angle of incidence established between the seed contact andthe interior surface of the pathway thus furthermore reducing the seedrattle and bounce as the individual seeds gravitationally travel alongthe pathway 60.

Configuring the seed tube with a narrowed front edge 80 extendingupwardly from the discharge end 68 of the tube 56 and along the majoritylength of the enclosed pathway 60 furthermore serves to reduce seedrattle and bounce as the seeds move along the pathway 60 thus promotingcontrol over the seeds gravitationally moving along the pathway andthereby promoting the ability to effect equidistant spacings betweenadjacent seeds planted in the furrows. According to the presentinvention, the narrowed front edge 80 extends beneath and across, in afore-and-aft direction, the ingress end 66 of the seed tube thusyielding further control over the gravitationally moving seeds as theypass between opposite ends of the seed tube. The angularly divergingsurfaces 82, 84 rearwardly extending from the front edge 80 furthermoreserve to positively direct the seeds toward a predetermined path ofmovement while minimizing seed bounce and rattle as the seeds move alongthe pathway. Because the narrowed front edge 80 is generally centralizedin a lateral direction relative to the pathway, the discharge of seedsfrom the tube 56 tends to remain constant thus yielding predictable andgenerally uniform discharge or dispensing of the seeds into the furrowin the ground Moreover providing at least the interior surfaceconfiguration of the tube with an extremely low coefficient of contactsurface friction allows the seeds, regardless of their size orconfiguration, to move along and contact the interior surface with noappreciable loss in speed as they move between increase and egress endsof the tube.

From the foregoing, it will be observed that numerous modifications andvariations can be effected without departing from the true spirit andscope of the novel concept of the present invention. It will beappreciated that the present disclosure is intended as anexemplification of the invention, and is not intended to limit theinvention to the specific embodiment illustrated. The disclosure isintended to cover by the appended claims all such modifications as fallwithin the scope of the claims.

What is claimed is:
 1. A seed metering apparatus comprising, in combination, a housing mounted to be moved over ground in a predetermined direction and having a hollow interior defining a hopper area wherein seeds are held, a rotary and apertured disk mounted within the hollow interior of said housing for conveying seeds from said hopper area to a seed discharge area under the influence of pressure differentials acting on said disk, and wherein the pressure differentials are blocked from acting on said disk in the region of said seed discharge area such that seeds are periodically released from said disk within the seed discharge area of the housing for deposit to the ground, and an elongated seed tube having an upper end arranged in a generally vertical orientation and in seed receiving relation relative to the seed discharge area of the housing and a lower end from which seeds are gravitationally discharged, said seed tube having an elongated and closed passageway including an internal surface defining a vertically disposed and narrowed front edge extending beneath and across, in a fore-and-aft direction, the width of the upper end of said passageway, said front edge further extending upwardly from a lower end of said tube and along the majority length of said tube with surfaces extending transversely away from and angularly diverging rearwardly in opposite directions relative to each other from said front edge toward a rear surface such that seeds discharged from said housing into said tube are positively directed and controlled thereby enhancing their delivery with predetermined spacing relative to each other as they are deposited onto the ground.
 2. The seed metering apparatus according to claim 1 wherein said passageway has a changing cross-sectional area between upper and lower ends of said tube.
 3. The seed metering apparatus according to claim 1 wherein the surfaces angularly diverging rearwardly in opposite directions relative to each other from said front edge define a "V" shaped configuration having an included angle ranging between about 60° and about 135° between the angularly diverging surfaces.
 4. The seed metering apparatus according to claim 1 wherein at least the front edge and the surfaces diverging rearwardly and in opposite angular directions relative to each other for at least a portion of the length of the closed passageway have a seed engaging surface having a coefficient of friction ranging between about 0.02 and about 0.10 to facilitate delivery of seeds between upper and lower ends of said tube.
 5. The seed metering apparatus according to claim 1 wherein said seed tube has a vertically curved configuration between opposite ends of said tube.
 6. The seed metering apparatus according to claim 1 wherein said seed metering tube is formed from a molybdenum disulfide filled nylon material to facilitate delivery of seeds between upper and lower ends of said tube thereby enhancing seed deposit on the ground.
 7. The seed metering apparatus according to claim 1 wherein said front edge has a curvature extending along the majority of the length thereof, said curvature having a radius ranging between about 0.062 inches and about 0.562 inches, and wherein said curvature extends outwardly away from said passageway and into planes of the diverging and angularly disposed surfaces extending rearwardly from said front edge.
 8. The seed metering apparatus according to claim 1 further including a sensor apparatus mounted between the upper and lower ends of said seed tube for monitoring the passage of seeds along said passageway.
 9. The seed metering apparatus according to claim 8 wherein said sensor apparatus comprises a photodetector including a light emitting source and an eye that receives light from said light emitting source.
 10. The seed metering apparatus according to claim 9 wherein the eye of said photodetector is mounted to extend through the front edge of said tube, and wherein the eye of said photodetector has a face that is configured to complement the internal surface of said closed passageway to substantially eliminate any interference with seeds passing thereover.
 11. The seed tube according to claim 9 wherein said seed tube is formed from a molybdenum disulfide filled nylon material to facilitate delivery of seeds between upper and lower ends of said tube thereby enhancing seed deposit on the ground. 